The maximum-likelihood rule for locating a frame-synchronization pattern in a direct-detection optical communication system employing eitherQ-ary pulse-position modulation or on-off keying is identified. We show that equivalent performance for the simple correlation and postdctection-correlation rules used in practice can require substantially more than a 3 dB increase in signal power o...
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This paper provides performance analyses of a broad spectrum of error-correcting codes in an antijam communication system under worst-case partial-band noise jamming conditions. These analyses demonstrate the coding advantages available for systems operating with and without frequency diversity. Utilizing both the exact approach (where possible) and upper-bounding approaches (Chernoff and union bo...
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The throughput of slotted ALOHA systems with multipacket message transmissions is evaluated. The conventional strategy of retransmitting the entire message when collisions occur results in a reduction in throughput when compared with the single packet case. However, it is proved analytically that the use of ARQ-type retransmission protocols can provide significant performance improvement. In parti...
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This paper introduces a repeater fault location system for a repeated submarine optical fiber transmission system of 400 Mbits/ s at 1.3μm. The repeater fault location system is used in an out-of-service test. The fault locator transmits a test signal via a main optical fiber line, in order to make a loop-back path in one of the repeaters for returning the test signals via another main optica...
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This paper describes a new line code which is suitable for a high-speed optical digital transmission system of more than 400 Mbits/s. This line code, namedmB1Ccode, is created by means of a complemental pulse which is inserted everymbits. This complemental pulse prevents long series of "l"'s or "0"'s. Power spectrum, jitter, and optical transmission characteristics as well as...
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The coding gain ofM-ary communication systems using orthogonal alphabets have been shown to improve by using concatenated orthogonal codes, each of lengthm = sqrt{M}. In the receiver, a two-stage MF/correlator and ML detection are utilized to provide the final decision through only2(m- 1)comparisons instead of the(M- 1)comparisons normally required. A co...
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In this paper, the calculation of the probabilityP_{f}(M, N)of more thanMbit errors in a block ofNbits transmitted over a Rayleigh fading channel using noncoherent frequency shift keying is considered. Accurate approximations toP_{f}(M, N)are derived under the assumption of very slow fading. Approximations are also given when a selection diversity system...
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The paper concerns the study of waiting times at a packet-switched merger node for which the outgoing capacity exceeds or is equal to the sum of the capacities of the incoming channels. The case of constant service times, fixed-length packets, and general independent inputs is considered. A trivial upper bound on the waiting time is derived. Exact results on waiting time are obtained for certain s...
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An adaptive approach to two-dimensional tree encoding of images is presented based upon the use of spatial masking concepts. Specifically, we make use of an adaptive encoding filter of the smoothing variety whose smoothing action is controlled by the local visibility of the encoding noise. The approach is an attempt to obtain an optimum compromise between slope overload and granular noise characte...
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Accurate phase and frequency transfer between mutually synchronized oscillators is a problem of current interest. This paper addresses a system of two mutually synchronized oscillators with inherently sinusoidal phase detectors. The system is studied in the context of nonlinear phase-locked loop theory. This is accomplished by Statistically characterizing the "time" and "space and time" increments...
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The Field-Lewinstein-Modestino model represents ELF noise as the sum of Gaussian and impulsive components. This model has proven to be accurate and is especially convenient for analysis and simulation. However, the parameters of the model are bandwidth dependent and have been measured for only a few specific bandwidths. No method of calculating the parameters for other bandwidths has been presente...
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In this work a new version of the cross-coupled phaselocked loop (CCPLL) interference canceller is presented. This detector consists of two phase-locked loop (PLL) demodulators interconnected in such a manner as to permit one PLL to lock onto and track the instantaneous frequency of the stronger received signal, while the other loop tracks and demodulates the weaker of two received signals. In add...
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The cost of a number of sequential coding search algorithms is analyzed in a systematic manner. These algorithms search code trees, and find use in data compression, error correction, and maximum likelihood sequence estimation. The cost function is made up of the size of and number of accesses to storage. It is found that algorithms that utilize sorting are much more expensive to use than those th...
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The spectrum-orbit utilization efficiency of satellite communications is becoming increasingly important. A first attempt is made in this paper to try to formulate the spectrum-orbit utilization efficiency in interference-limited situations by defining the self-efficiency for a single satellite, and the cross-efficiency and coordination efficiency for each pair of adjacent satellites. The various ...
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The Middleton Class A narrow-band non-Gaussian noise model [9]-[12] is examined. It is shown that this noise model (which is known to fit closely a variety of non-Gaussian noises) can itself be closely approximated by a computationally much simpler noise model. It is then shown by numerical examples that, for the problem of locally optimum detection, the simplest form of this approximation yields ...
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-A model of a moving-boundary, fixed frame length, integrated multiplexor is proposed and analyzed. The assignment of slots within a frame to the voice and data sources is made by an allocation function. The joint distributions of queue length and expected waiting time are derived.
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The effects of nonzero-centroid and skewness of a fading spectrum are shown to influence the binary error probabilities of incoherent FSK and differentially coherent phase-reversal (DPSK) matched-filter receivers. It is also shown that for incoherent FSK, the skewness or nonzero centroid in the fading spectrum causes different error probabilities for binary signals, resulting in a binary asymmetri...
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